1. Field of the Invention
The present invention relates generally to multi-digital subscriber line access processes and multiplexor systems (i.e., M-DSLAM systems) using asynchronous transfer mode (i.e., ATM) networks as backbone networks, and, more particularly, to processes and multi-digital subscriber line access processes and multiplexor systems able to provide various wideband high-speed data services at high capacity for numerous subscribers connected from the opposite site of the M-DSLAM system.
2. Description of Related Art
Generally, a digital subscriber line (i.e., generally known as a “DSL”) provides a wideband high-speed data service in both directions for home or office through a normal telephone line made of copper, strung as a twisted pair cable.
There are various kinds of the DSL, collectively called xDSL in common, such as an asymmetric digital subscriber line (referred to as an “ADSL”), a high bit-rate digital subscriber line (referred to as a “HDSL”), a symmetric high speed digital subscriber line (referred to as a “SHDSL”), and a very high data rate digital subscriber line (referred to as a “VDSL”). Among the xDSL services, the ADSL service is widely used to provide a high-speed data service for a home user as well as for small and medium-sized companies. The configuration of a typical ADSL may be analyzed in order to understand the problems that I have discovered in conventional xDSL systems.
Usually, the typical asymmetric digital subscriber line (that is, the ADSL) system has a digital subscriber line access multiplexor (i.e., a “DSLAM”), a DSLAM manager, an ADSL transmission unit-receiver, and a signal splitter.
The DSLAM system is positioned in the configuration of the typical asymmetric digital subscriber line system to serve as an access node to an access network, such as an ATM network and a public switched telephone network (i.e., a “PSTN”) by collecting individual, discrete subscriber's lines.
ADSL systems based on an ATM network, may connect subscribers to an Internet service provider and provide ADSL service, such as the Internet service, and plain old telephone service (i.e., “POTS”) for those subscribers.
A DSLAM system using the ATM network as a backbone network, receives data from the ATM network through an ATM network connection port, extracts an ATM cell from the received data, performs ATM cell processing according to the information from the ATM cell, converts the ATM cell to an analog signal, and transmits the analog signal to an ADSL transmitter unit receiver through the ubiquitous twisted, copper wire pair telephone line sequentially in order to provide high-speed data ADSL transmission and reception service between the subscriber and the ISP network.
I have discovered that it is difficult to provide some of the various services recently requested by subscribers, such as video on demand (i.e., “VOD”), videoconferencing, video medical services, and voice service based on a voice over Internet protocol (i.e., VoIP”), as well as conventional Internet service and voice dialogue service, because various units and data processing ability with high-capacity data processing ability are required. Conventional DSLAM systems have a limited capacity. It is difficult therefore, to provide various services, such as VoD and VoIP, to subscribers, in addition to providing Internet services to those subscribers.
I have also found that conventional DSLAM systems are connected to subscribers by a single ISP network through the ATM network. The flexibility of conventional DSLAM systems is inferior, and it is impossible to provide multiple ISP services to subscribers from numerous ISPs. Moreover, the port density of conventional systems is low and the extendability of the system diminished. Furthermore, as the number of the subscribers in a densely inhabited district increases, the number of DSLAMs increases. Consequently, the area occupied by the DSLAM is inevitably increased.
In my opinion, there is an urgent requirement to develop a M-DSLAM system having a greater data processing ability, and to provide various acceptance units in order to make it possible to link subscribers with numerous distinct Internet service providers (i.e., “ISPs”).